Method must have a return type?!?

Question

I am getting an error on line 68 Method must have return type. Please help!

using

System;

using

System.Collections.Generic;

using

SC = System.Console;

using

System.Linq;

using

System.Text;

public

class abc

{

   

public static void Main()

    {

       

String continueStr = "Y";

       

double side, length;

       

SC.WriteLine("Lab has started for ");

       

while (continueStr.ToUpper()!="N")

        {

           

SC.Write("\nEnter the value for side ");

            side =

Convert.ToDouble(SC.ReadLine());

           

while (side < 0)

            {

               

SC.WriteLine("The side may not be Negative! Please re-enter");

               

SC.Write("Enter the value for side ");

                side =

Convert.ToDouble(SC.ReadLine());

            }

           

SC.Write("\nEnter the value for length ");

            length =

Convert.ToDouble(SC.ReadLine());

           

while (length < 0)

            {

               

SC.WriteLine("The width may not be Negative! Please re-enter");

               

SC.Write("Enter the value for length ");

                length =

Convert.ToDouble(SC.ReadLine());

            }

           

if (length == 0 && side == 0 )

            {

               

Prism myPrism = new Prism(side, length);

                myPrism.displayData();

            }

           

else (length >= 0 && side >= 0 );

            {

               

Prism myPrism = new Prism(side, length);

                myPrism.displayData();

            }

           

SC.Write("\nWould you like to enter more data (Y/N) ");

            continueStr =

SC.ReadLine();

        }

       

SC.WriteLine("\nLab has successfully terminated for ");

    }

// end of Main method

}

// end of Main class

public

class Square

{ 

private double side;     //in a square, both sides are the same

   

public Square ()

    {  

// default constructor

         side = 7;

    }

   

public Square (double s)

    {   side = s;

    }

   

public getSide()           // a getter method

    {  

return side;

    }

   

public double findArea()

    {  

return (side * side);

    }

}                                                                                            

// see the next page for more                                       

public

class Prism : Square

{

   

private double side;

   

private double length;

   

public Prism():base()

    {

        length = 10;

//default constructor

    }

   

public Prism(double s, double l):base(s,l)

    {

        length = l;

// non-default constructor

    }

   

new public double findArea()

    {

       

double squareArea;

        squareArea =

base.findArea();

        getSide =

Math.Sqrt((((5.1 / 2) * (5.1 / 2)) + (9.2 * 9.2)));

       

return Math.Round((2 * squareArea) + (5.1 * 6.7) + (2 * (getSide * 6.7)), 2);

    }

//???

   

public double volume()

    {

       

return Math.findArea() * length ;

    }

   

public void displayData()

    {

       

SC.WriteLine("\nThe side of the Prism is {0,5}",

       

Math.Round(side, 2).ToString("F2"));

       

SC.WriteLine("\nThe length of the Prism is {0,9}",

       

Math.Round(length, 2).ToString("F2"));

    }

   

// code a default constructor, another constructor, a method for the volume,

  

// and a method named findArea() for the surface area; Also code getter method for the length

  

// value and a method named displayData within the Prism class to print the desired output.

}